Esters of acids of phosphorus



Patented June 18, 1935 {PATENT OFFICE 2,005,619 ESTERS oF'Acms orPHOSPHORUS George De Witt Graves, Wilmington, Del assignor to E. I. duPont de Nemours & Company, Wilmington, DeL, a corporation of Delaware NoDrawing.

' Application November 10, 1934,

Serial No. 752,465

22 Claims;

This invention relates to new mixtures of esters and mixed esters ofphosphorus acids derived from a-cyclic monohydric alcohols and methodsfor making the same. By a-cyclic is meant an open carbon chain.

Some esters of phosphorusacids derived from aliphaticalcohols and fromphenols are known and have been employed in cellulose derivative plasticand coating compositions and as wetting agents, detergents, textilelubricants and the like. Among the known phosphoric esters-are those oflow molecular weight a-cyclic monohydric alcohols, containing forexample five or less carbon atoms. However, such esters do not have asufficient surface active effect to render them commercially valuable aswetting agents and detergents. The homogeneous phosphorimacid esters oflong chain aliphatic alcohols and of phenols e. g. tri o-cresylphosphate, dilauryl phosphate,

and dicetyl phosphate, are also known. Such esters have been limited inapplication for the reason that they tend to exude from plastic andcoating compositions containing them, or they are not sufficientlysoluble in water and oils.

An object of the present invention is to provide mixtures of esters andmixed esters of phosphorus acids derived from long chain a-cyclicalcohols which mixed esters are new chemical compounds. A further objectis to provide methods for making such new compounds. Still furtherobjects are to provide new compositions of matter and to advance theart. Other objects will appear hereinafter.

These objects may be accomplished in accordance with my invention whichcomprises making mixtures of neutral and/or acid esters of the acids ofphosphorus. The mixtures ofesters apparently contain'mixed esters eachof which contains at least one radical of a primary monohydric a-cyclicalcohol of at least 8 carbon atoms and at least one member of the groupcomprising phenolic radicals and primary monohydric acyclic alcoholradicals different from the first mentioned alcohol radical. In otherwords, a mixed ester of my invention contains at least two different'a-cyclic alcohol radicals or a-cyclic alcohol radicals and phenolicradicals, at least one a-cyclic alcohol radical containing at least 8carbon atoms and, preferably, between 8 and 18 carbon atoms. Thepreferred compositions of my invention are the mixture of esters andmixed esters obtainable by reacting an esterifying derivative oforthophosphoric acidwith a mixture of alcohols obtainable from thecarboxylic reduction of naturally occurring fatty oils such as sperm oiland coconut 'oil. One method of obtaining such alcohols is disclosed inapplication Serial No. 584,575 filed January 2, 1932 by Wilbur A.Lazier.

The mixtures of esters and mixed esters of my invention include theesters of orthophos- 5 phoric acid, metaphosphoric acid, pyrophosphoricacid, phosphorous acid and hypophosphorous acid. They also includeesters of mixtures of the acids of phosphorus.

The compositions of my invention may be, pre- 10 pared by reacting amixture of a-cyclic alcohols of at least 8 carbon atoms or a mixture ofsuch alcohols containing a phenol or some other acyclic alcohol with aphosphorus chloride or anhydride. Such mixture of alcohols must containat least one molecular proportion of alcohols of at least 8 carbon atomsand at least one molecular proportion of a difierent alcohol or a phenolfor each molecule of the phosphorus compound.

The mixed esters may also be prepared by first preparing an, acid esterof an acid of phosphorus with an a-cyclic alcohol or mixture of a-cyclicalcohols and then further reacting the acid ester with other a-cyclicalcohols or phenols. This latter method produces the pure mixed esters,i. e. 25 mixed esters only unmixed with homogeneous esters.

The process of making mixtures of a-cyclic alcohol'esters ofortho-phosphoric acid may be carried out by placing a mixture of suchalcohols, alone or dissolved in a suitable solvent such as benzene,toluene, chloroform and the like, in an acid-resistant vessel connectedwith a reflux condenser under reduced pressure. The vessel and itscontents is then brought to the desired temperature which may be fromabout 0 to about 100 C. It will usually be found preferable to em ploytemperatures of about 0 to about C. Phosphorus oxychloride is thengradually admitted in liquid or vapor form. The bulk of the 40 hydrogenchloride, formed during the addition of the oxychloride, is continuouslyremoved.

When all of thephosphorus oxychloride has been added and the reaction iscomplete, the mixture is heated under reduced pressure until thehydrogen chloride vapors have almost entirely passed out of the vessel.If desired, the ingredients may be mixed in the cold and the reactionthen carried to completion under reduced pressure in a heated vessel.The resulting mixture of phosphates may be purified by distillationunder reduced pressure or by recrystallization from a suitable solventsuch as ,benzine, alcohols or mixtures of alcohols with water.

Another procedure consists in reacting one ture of primary a-cyclic.alcohols of eight, or more carbon atoms, preferably in the cold'and in asuitable'solvent, and then heating a short time under'reduced pressure.The operation is preferably carried out at a temperature of betweenabout, 0 to about 30 -C. The product will be principally the chloridesof a mixture of monoalkyl phosphates or dialkyl phosphates, dependingupon the quantity of the alcohol mixture employed. 'After removal of thehydrogen chloride, a second alcohol or phenol or mixture of alcohols isadded, preferably in excess, and the neutral mixed esters are obtained.

Catalysts such as copper powder or metallic.

chlorides may be added to the reaction liquid in order to facilitate thesplitting ofi of the hy; drogenchloride and to speed up the reaction.The degree of reduced pressure employed may also vary within widelimits.

In place of the phosphorus oxychloride, other phosphorus chlorides oroxides such as phosphorus pentachloride, phosphorus trichloride andphosphorus pentoxide may be employed. When phosphorus pentoxide isemployed, the, solvent may be ether, pyridine or other tertiary base.With either phosphorus .pentachloride or phosphorus pentoxide, the mixmay be heated onv the water bath. The solvent may be removed bydistillation and then the product washed with water and dried by heatingunder reduced pressure. Also, the mixed alcohols may be reacted withsodium to produce; the alkoxides which may then be reacted withphosphorus oxychloride or phosphorus trichloride.

A further and alternative procedure of making the mixture ofesterscomprises first preparing the mixed alkyl halides, such as theiodides, and then reacting them with the silver salt of pyrophosphoric,metaphosphoric or orthophosphoric acids to obtain the mixture of neutralor acid alkyl esters, depending upon the proportions employed. I

The mixture of esters and the mixed esters of my invention are, ingeneral, liquids or semi-liquids at atmospheric temperatures i. e. aboutC. This is a surprising result as the corresponding pure homogeneousesters are generally solids at such temperatures. Also, when two .ormore such homogeneous esters are melted together, the

product is solid at such temperatures, For exam ple when equal parts ofdilauryl phosphate, having a melting point of 60 C. dicetyl phosphate,having a melting point of 74 C., are fused together, the resultingproduct has a melting point of about 67-69" C.

The neutral esters may be treated with alkali to produce the alkalisalts of the dialkyl phosphates. For example, one part by weight of amixturen of neutral phosphates is boiled. with eight parts by weight ofsodium hydroxide dissolved in 192 parts by weight of water for twohours. The sodium salts of the .dialkyl phosphates are thus obtained.These salts are soluble or dispersible in water. It has been found thatthesodium salts of a mixture of dialkyl phosphates can be employed toemulsify an oil or a long chain alcohol in a small amount of water toobtain a thick jelly which can be diluted indefinitely with water.

While the sodium salts of the acid esters of phosphorus acids aresoluble in water, the salts, obtained with organic bases such astriethanolamine or methyl glucamine, are even more soluble. The neutralesters may also be hydrolyzed by cooking them' with'acids to yield'acidsof the monoand'thedialkyl'phosphates. J

. In orderto illustrate my invention more clearly and the preferredmodes of carrying the same into effect, the following examples aregiven:

I Example; 1

A mixture ofapproximately"60% lauryl alcohol and 40% myristyl alcohol,which mixture had an dlcated molecular weight ,of' 206 as calculategfrom an analytical determination of by droxyl number, was prepared. 247parts by weight of thismixture was mixed with 300 parts of benzene- 61.4parts by weight of phosphorous oxychloride was then added'slowly. Theresulting mixture ,wasplaced' ina glass vessel attached to a reflux;condenser and-heated at the reflux temperature-undera pressure of 725mm. for 18 hours. Theslightvacuum served to assist in the removal of thehydrogenfchloride which was formed. The benzene solution. was thenwashed with warm water until neutral and, the benzene evaporated. Thedetermination of the acid number indicated the product to be a'mi'xtureof dialkyl acid orthophosphates of lauryl and myristyl alcohols-andprobably contained substantial amounts of the mixed lauryl, myristylacid orthophosphate. The product wasj a liquid which, when neutralizedwith sodium hydroxide, was sol-' uble in waterand formedastable'dispersion.

The product is not completelysolid zat15 C. and becomes a liquidwhenheatedtogabout C. This is surprising as dilauryl phosphate melts {at60 0., dimyristyl phosphate melts atabout 67C. and it was expected thata mixture of approximately equal parts of dilauryl phosphate and di-,

myristyl phosphate would melt at a above 60 C.

Example 2 A mixture of alcohols was obtained by hydrogenation of spennoil. dicated molecular weight of 272, as calculated from an analyticaldetermination of hydroxyl number, and had approximately the followingcomposition: Unsaturated alcohols oftemperature This mixture had an in-Per cent 12 carbon atoms 0.8 14 carbon atoms 6.4 16 carbon atoms 21.4 18carbon atoms oleyl) 34.9 20 carbon atoms 12.4 22 carbon atoms 0.4Saturated alcohols of- I v Per cent 10 carbon atoms 1.0

12 carbon atoms 3.7

14 carbon atoms 5.9 16 carbon atoms 4.9 18 carbon atoms -4 7.2 20 carbonatoms 0.7

272 parts by weightof the above mixture was After evaporation of thebenzene, a light yellow colored liquid was obtained. This product appeared to be a mixture of esters of orthophosphoric acid includingsubstantial amounts of the mixed esters.

Example 3 500 parts by weight of a mixture of octyl, decyl, and laurylalcohol was placed in a vessel resistant to hydrochloric acid, alongwith 500 parts by weight of benzene, and cooled to between 0 and 20 C.243.5 parts of phosphorus oxychloride was added slowly with agitation.During the addition of the phosphorus oxychloride, the temperature wasmaintained at or below 20 C. After the addition of the phosphorusoxychloride, the mixture'was agitated at about 20 C. for 2 hours.

cold water until it was free from chlorides. The

resulting solution was separated from the water,

dried and the benzene evaporated off. The final product was a slightlyyellowish oil containing approximately 95% of a mixture of dialkylphosphates containing a substantial proportion of mixed dialkylphosphates. I This product may be decolorized by treating with charcoaland filtering.

The alcohol mixture of the above example was a mixture of primaryaliphatic alcohols havingan average molecular weight of about 157.5 andcontaining .n-octyl, n-decyl and lauryl alcohols. It was obtained by thefractionation of the alcohol mixture obtained by the hydrogenation ofcoconut oil or oil acids by the process of Lazier, Serial Number584,575, filed January 2, 1932.

Example 4 and was a mixture of primary monohydric aliphatic alcoholscontaining approximately 2% hexyl alcohol, 9% octyl alcohol, 10% decylalcoho], 45% lauryl alcohol, 20% myristyl alcohol, 7% cetyl alcohol, 5%stearyl alcohol and 2% oleyl alcohol. 519 parts by weight of thismixture was dissolved in 750 parts by weight of benzene. 459 parts byweight of phosphorus oxychloride was added slowly, maintaining thetemperature at about 25 to 30 C. by cooling. The mixture was allowed toreact for five hours under a sufficient vacuum to cause the benzene toreflux at the temperature of 25-30" C. The solution was then washed withwater and the benzene evaporated. A light colored oil remained. Thisproduct is a mixture of alkyl phosphates containing a substantialproportion of mixed phosphates in which the alkyl group has an evennumber of carbon atoms in the range 618 inclusive.

Example 5 The alcohol mixture used in Example 4 may also be used inExample 3 with the slight variations in proportion of POCla to mixedalcohols which is necessary to take care of the slightly differentaverage molecular weight of the latter. A product consisting of amixture of alkyl phosphates, the alkyl radicals having an even number ofcarbons in the range 618 inclusive, is obtained.

Example 6 186 parts by weight of lauryl alcohol was dis- The mixture wasthen washed with solved in 220 parts by weight of benzene. 296 parts byweight of dicresyl phosphoryl chloride was added to the solution. Thesolution was then refluxed for 17 hours at about C., after which it waswashed with warm water until neutral. Evaporation of the solvent left alight yellow colored oil which analysis for phosphorus indicated to bethe neutral dicresyl lauryl phosphate.

Theabove examples are merely illustrative of my invention. Other newmixed esters of the acids of phosphorus which may be prepared are:

'Acid octyl, decyl ortho-phosphate Acid hexyl, stearyl ortho-phosphateAcid lauryl, phenyl ortho-phosphate Acid oleyl, cresyl ortho-phosphateNeutral hexyl, lauryl, stearyl orthq-phosphate Neutral dilauryl, ethylortho-phosphate Neutral myristyl, octyl, cresyl ortho-phosphate Neutralbutyl, nonyl, oleyl ortho-phosphate Neutral di-eleostearyl, decylortho-phosphate Neutral diricinoleyl, decyl ortho-phosphate Neutraloctyl, lauryl, stearyl phosphite Neutral lauryl, myristyl, hypophosphiteAcid undecyl, myristyl, heptadecyl pyrophosphate I Mixed esters ofmeta-phosphoric acid derived from a mixture of alcohols obtained fromcoconut oil and composed essentially of octyl,

decyl, lauryl, myristyl and cetyl alcohols. In the compounds listedabove, the term i'icinoleyl represents the radical of ricinoleyl alcoholobtained from castor oil by sodium reduction. The term eleostearylrepresents the radical of eleostearyl alcohol which is obtained bysodium reduction ofChina-wood oil.

, Many other compounds, similar to those heretofore mentioned, will beapparent to those skilled in the art.

The mixture of estersand mixed esters of my invention are valuablematerials which may be employed as plasticizers for plastic and coatingcompositions and particularly for such compositions containing celluloseethers and esters to be used on wood, metal, cloth, or paper. They havemany advantages over prior phosphate esters in that they do not tend toexude from such plastic and coating compositions and are also moresoluble in such compositions. They also have fire-retarding properties.

The acid esters and their alkali, ammonia and amine salts are useful aswetting agents, deterwater and oils, and have a marked surface activeeffect. For example, sodium ethyl lauryl phosphate is more soluble inwater than sodium dilauryl phosphate.

Also, the acid phosphates, when added to lubricating oils, maintain aneffective lubricating action at excessive pressures. The mixture ofesters and the mixed phosphates, such as oleyl lauryl phosphate, aremore soluble in the lubrieating oils than the pure homogeneousphosphates, such as dilauryl phosphate and dioleyl phosphate and arehence more effective.

The cobalt and manganese salts of the ,acid phosphates of my inventionare catalysts for the oxidation of drying oils. Also, the iron, nickel,cobalt and manganese salts of my acid phosphates retard the absorptionof ultra-violet light application is a continuation in part of theco-pending application of Bousquet, Graves and Salzberg, Serial No.649,448 filed December 29, 1932.

While I have disclosed the preferred embodiments of my invention andindicated some of the variations and modifications which may be madetherein, it will be readily apparent to those skilled in the art thatmany other variations and modifications may be made therein withoutdeparting from the spirit of my invention. Accordingly, the scope of myinvention is to be limited solely by the appended claims construed asbroadly as is permissible in view of the prior art.

I claim:

1. A mixture of esters of an acid of phosphorus obtainable by reactingone molecular proportion of an esterifying derivative of an acid ofphosphorus with a mixture of alcohols containing at least one molecularproportion of primary monohydric a-eyciie alcohols of at least 8 carbonatoms and at least one molecular proportion of at least one member ofthe group consisting of phenols and primary monohydric a-cyclic alcoholsdifferent from one of the first mentioned alcohols.

2. A mixture of esters of an acid of phosphorus obtainable by reactingone molecular proportion of an esterifying derivative of an acid ofphosphorus with at least two molecular proportions of a mixture ofprimary monohydric a-cyclic alcohols obtainable by the carboxylicreduction of a naturally occurring fatty oil.

3. A mixture of esters of an acid of phosphorus obtainable by reactingone molecular proportion of an esterifying derivative of an acid ofphosphorus with at least two molecular proportions of a mixture ofprimary monohydric a-cyclic alcohols obtainable by thecarboxylicreduction of coconut oil.

4. A mixture of esters of an acid of phosphorus obtainable by reactingone molecular proportion of an esterifying derivative ofortho-phosphoric acid with a mixture of alcohols containing at least onemolecular proportion of primary monohydric a-eyclic alcohols of at least8 carbon atoms and at least one molecular proportion of at least onemember of the group consisting of phenols and primary monohydrica-cyclic alcohols different from one of the first mentioned alcohols.

5. A mixture of esters of an acid of phosphorus obtainable by reactingone molecular proportion of an esterifying derivative ofortho-phosphoric acid with at least two molecular proportions of amixture of primary monohydric acyclic alcohols obtainable by thecarboxylic reduction of a naturally occurring fatty oil.

6. A mixture of esters of an acid of phosphorus obtainable by reactingone molecular proportion of an esterifying derivative of.ortho-phosporic acid with at least two molecular proportions of amixture of primary monohydric a-cyclic alcohols obtainable by thecarboxylic reduction of coconut oil.

7. Mixed esters of an acid of phosphorus, each ester containing at leastone radical of a primary monohydric a-cyclic alcohol of at least 8carbon atoms and at least one member of the group consisting of phenolicradicals and primary monohydric a-cyclic alcohol radicals difierent fromthe first mentioned alcohol radical.

8. Neutral mixed esters of an acid of phosphorus, each ester containingat least one radical of a primary monohydric a-cyelic alcohol of atleast 8 carbon atoms and at least one member primary monohydric a-cyelicalcohol radicals different from the first mentioned alcohol radical.

9. Mixed esters of ortho-phosphoric acid, each ester containing at leastone radical of a primary monohydric a-cyclic alcohol of at least 8carbon atoms and at least one member of the group consisting of phenolicradicals and primary monohydric a-cyclic alcohol radicals different fromthe first mentioned alcohol radical.

10. Neutral mixed esters of ortho-phosphoric acid, each ester containingat least one radical of a primary monohydric a-cyclic alcohol of atleast 8 carbon atoms and at least one member of the group consisting ofphenolic radicals and primary monohydric a-cyclic alcohol radicalsdifferent from the first mentioned alcohol radical.

11. Mixed esters of ortho-phosphoric acid, each ester containing atleast one radical of a primary monohydric a-cyclic alcohol of 8 to 18carbon atoms and at least one member of the group consisting of phenolicradicals and primary monohydric a-cyclic alcohol radicals diflerent fromthe first mentioned alcoholv radical.

12. Neutral mixed esters of ortho-phosphoric acid, each ester containingat least one radical of a primary monohydric a-cyclic alcohol of 8 to 18carbon atoms and at least one member of the group consisting of phenolicradicals and primary monohydric a-cyelic alcohol radicals different fromthe first mentioned alcohol radical.

13. A mixture of mixed esters of an acid of phosphorus, each estercontaining at least one radical of a primary monohydric a-cyclic alcoholof at least 8 carbon atoms and at least one radical of la difierentprimary monohydric a-cyclic alco- 14. A mixture of neutral mixed estersof an acid of phosphorus, each ester containing at least one radical ofa primary monohydric a-cyclic alcohol of at least 8 carbon atoms and atleast one radical of a difierent primary monohydric a-cyclic alcohol.

15. A mixture oi. mixed esters of ortho-phosphoric acid, each estercontaining at least one radical of a primary monohydric a-cyclic alcoholof 8 to 18 carbon atoms and at least one radical of a difierent primarymonohydric a-cyclic alcohol.

16. A mixture of neutral mixed esters of orthophosphoric acid, eachester containing at least one radical of a primary monohydric a-cyclicalcohol of 8 to 18 carbon atoms and at least one radical of a difierentprimary monohydric acyclic alcohol.

17. The method of making mixtures of esters of an acid of phosphoruswhich comprises reacting a mixture of primary'monohydric a-cyclicalcohols with one molecular proportion of an esterifying derivative ofan acid of phosphorus, said mixture of alcohols containing at least onemolecular proportion of a-cyclic alcohols of at least 8 carbon atoms andat least one molecular proportion of a difierent a-cyclic monohydricalcohol.

18. The method of making mixed esters of an acid of phosphorus whichcomprises reacting one molecular proportion of an esterifying derivativeof an acid of phosphorus with from 1 to 2 molecular proportions of atleast one member of the group consisting of phenols and primarymonohydric a-cyclic alcohols, and then reacting the resulting productwith at least one molecular proportion of a member of the groupconsisting of primary monohydric alcohols of at least 8 carbon atoms andmixtures of such alcohols.

tion of an esterifying derivative of ortho-phosphoric acid with at leasttwo molecular proportions of a mixture of primary monohydric a-cyclicalcohols obtainable by the hydrogenation of sperm oil.

22. A mixture of esters of ortho-phosphoric acid obtainable by reactingone molecular proportion of an esterifying derivative ofortho-phosphorlc acid with at least two molecular proportions of amixture of alcohols of which the greater proportion consists of amixture of primary monohydric a-cyclic unsaturated alcohols of 16, 18and 10 20 carbon atoms.

GEORGE DE WI'I'I GRAVES.

